The present invention relates to battery containment devices, and more particularly to a lithium battery containment device adapted for fire prevention.
Lithium batteries provide a power source for a variety of products including portable consumer electronic devices such as thermostats and smoke/carbon monoxide alarms. Attempts have also been made to incorporate lithium battery technology into electronic door locks.
Electronic door locks, as opposed to pure mechanical locks, need a power source to operate the locking and control mechanism. In battery operated electronic door locks, power is obtained from a set of batteries installed in the lock. The most commonly used batteries in electronic door locks are alkaline batteries. The service life (the time after which the batteries need to be replaced) depends on the usage of the lock, but is typically two to three years for normal usage doors. More recently, attempts have been made to increase battery service life by incorporating additional types of battery technology including lithium battery technology. However, practical application of lithium battery technology in electronic door locks has failed due in part to the adverse affect lithium technology has on the integrity and specifications of fire rated doors. Lithium batteries adversely affect the integrity and specifications of fire rated doors because the batteries can violently deflagrate and experience severe outgassing when exposed to temperatures representative of that found during a building fire. The violent deflagration of the lithium batteries has the undesirable effect that it can cause the fire on one side of the fire rated door to propagate to the other side and hence compromise the intended function of a fire door.